The present invention relates to a transporting apparatus suitable for transporting articles and more particularly, for transporting divertor modules into and out of a nuclear fusion reactor.
In general, the interior of a nuclear fusion reactor is under a strong influence of radiation as a result of the fusion reaction, with level of the residual activity being high even after the stop of operation of the reactor, so that operators or engineers cannot enter into the reactor. Various maintenance and repair works, therefore, have to be made fully automatic. Accordingly the reactor should be designed to be easily maintained and repaired by remote control. Namely, the reactor has to be designed by taking into account the ease of maintenance and repair works by remote control. Among the constituents in the nuclear fusion reactor, the divertor, installed in a vacuum vessel to get rid of impurity ions in the reactor, is subjected to an extremely severe condition and hence has to be renewed or repaired within a short period of time. From this point of view, there have been several proposals in which the divertor is divided into a plurality of modules for the repair and/or the renewal thereof, as well as apparatus for effecting such renewal.
According to a first proposal, the vacuum vessel containing the divertor and a shield structure around the vacuum vessel are divided into a plurality of sections. The repair is made by shifting the shield structure sections to the repairing place. An example of this proposal is disclosed in, for example, "PROCEEDINGS OF THE 28TH CONFERENCE ON REMOTE SYSTEM TECHNOLOGY" America Nuclear Society, 1980. A disadvantage of the proposal resides in the fact that, in shifting of the structure section together with the diverter module, since the structure section is extremely heavy, the shifting requires a large amount of energy. Consequently, this proposal does not seem to be readily realized.
According to a second proposal, a repairing machine is brought into the vacuum vessel and the divertor module is repaired in the vacuum vessel; however, this proposal can hardly be put into practice because of the problems concerning the radio resistance and reliability of the repairing machine.
According to a third proposal, the divertor module is put into and out from the vacuum vessel through a maintenance port or window formed in the wall of the vacuum vessel. This proposal affords an efficient operability when the divertor module is shifted only linearly through the port. In this method, in order to effect a linear shifting of the divertor module it is necessary for the number of the divided divertor modules to be equal to the number of toroidal field coils. Consequently, the size of the modules becomes larger, so that a greater space is required between adjacent coils for shifting the modules through the space. This in turn requires the toroidal field coil to have an impractically large diameter. The reactor to be applied with this method is restrained of its size. In addition, this method cannot be applied to the reactor in which two divertor units are respectively arranged in upper and lower portions of the interior of the vacuum vessel as a so-called "double divertor type". Thus, this proposal is also impractical because it deteriorates the performance of the reactor and increases the size of the same.
In order to avoid the problems encountered in the above proposals it has further been proposed to divide the divertor into a number of modules which is greater than that of the toroidal field coils, thereby reducing the size of each module and a module group consisting of at least three modules replaced through a maintenance port. According to this proposal, the divertor modules should be circumferentially moved around the center of the reactor within the vacuum vessel. To this end, additional equipment is required to readily effect the circumferential shift of the modules in the vacuum vessel with certainty.